Adjustment limiting means



Oct. 12, 1954 s. GAJEWSKI nu.

ADJUSTMENT LIMITING MEANS Filed June 25, 1952 Patented Oct. 12, 1954 ADJUSTMENT LIMITING MEAN S Stefan Gajewski', Greenfield, andRobertLKonle, New Berlin Township, Waukesha County, .Wis., assignors to Cutler-HammenInc Milwaukee, Wis., a corporation of Delaware Application'June-25; 1952, Serial No. 295,464

9 Claims. (01. ZOO-83) This invention relates to adjustment limiting. means, and while not limited thereto isparticularly applicable to pressure responsive switches-as are used for controlling electric refrigerators.

Pressure responsive switches, and especially. those employing spring biasing. means, must necessarily be equipped with means toadjust the pressure at which the switch will operate, or, more specifically, to adjust the spring pressure of those switches employing spring biasing means. Such adjustments are necessary so that the switches can be mass produced and subsequently calibrated and put into final adjustment when.the actual operating conditions have been ascertained. Pressure systems require switches which are'ad justable to operateat different pressures; but which for safety reasons cannot be tampered with to. effect an adjustmentwhich will allow the pres-- sure of' the system to exceed a predetermined safe maximum value.

Therefore, this invention has among its-objectives to provide an adjusting. means which: is. operable to vary the pressure at: which the. pressure responsive switch will be actuated, but which is incapable of being adjusted'beyond apredetermined safe limit.

Another object is to provide a ruggedand-compact control device of the aforesaid character which consists of a relatively small number of parts which can be readily and inexpensively manufactured and assembled.

Another object is to providean adjusting'means of the aforementioned character which cannotv be forced beyond the maximum safe limit to which it has been set.

The novel features which I consider characteristic of my invention areset forthwith particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together'with additional objects and advantages thereof, will best be understood from the following description of specific. embodiments when read in connection withthe accompanying drawings, in which:

- Figure 1 is a side elevational view, shown partly;

in section, of a control device embodyingzthe in-- vention;

Fig. 2 is aside elevational View of the'adjusting means from Fig. 1, shown partly in section to illusa trate the adjustment limiting structure; and:

Fig. 3 is a side elevational view, shown partly in section, of a modified formof the deviceshown; in Figs. 1 and 2.

Similar reference characters indicate corresponding parts throughout the several. views of the drawings.

Referring to Fig. 1, the numeral I designatesa. base member having. thereon a switch mechanism 2 including a stationary (2011133017301? set ofv contacts oneofwhich is shown at 3.-and amovable contactor or. bridging contactor 4. Saidcontactor 4 is responsive to operation ofaswitch ac-- tuating arm 5, and appropriate overcenter snap acting spring. arrangements, not shownin detail. Such switch construction and operation isclearly show-n and described in- Kuhn Patent No. 2,158,824, Circuit Controlling Device, wherefore applicant relies upon said patent for detailed-information concerning the switchmechanism 2. Said actuating. arm. 5 is responsive to fluid pres-- sure in the line 6, or, more specifically, to the fluidpressurewithina bellowsI. Saidbellows 'I is enveloped-by a casing 8; whichis attached to the base member l by fastening means suchas screws or bolts 9.

Base member I is formed with an opening affording. clearancefor a linking member I0 which transmits the pressure of the fluid in bellowsl.

to the actuatingarm 5 of switch mechanism 2. Said actuating arm. 5. is biased into a given position by means of a compression spring. I I.

Said spring I I is held-in engagement with said actuating arm Erby meansof. a U-shaped cover receiving bolts 9 so as to hold-said cover in rigid engagement withsaidbasemember I. The force.

ofsaid spring. II against the actuating arm 5-isvaried by. means ofthe adjusting mechanism I3 to thereby permit said switch mechanismi tobe operable at any, desired fluid pressure.

Said adjusting. mechanism I3 (see Fig. 2) comprises-a stud. I4,,an.adjusting. nut I5, a screw member I6-, a=sleeveI1 and-.a locking. member I8..

Said stud-I4 has anexternally. threaded body portionit, and a cylindrical end portion I4 Formed. integrally with said end portion: M is an. annular shoulder I4 anda transverse slot. M 'of' suchsize as to receive the end of an ordinary; screwdriver.

threaded throughout its entire length,

Adjusting nut. I 5' is I constructed with an; an'-- nular groove' of such sizet as-to afford: a bearing engagement between: said adjusting v nut. I5. and. stud I4,-,as shown=in- Fig. 2. Said adjusting nut;

5 theside wallofithe U shaped cover I2 5 Such ar- Said. U-shaped cover. I2 is formed with. flange portionshaving.openings for threadedly- Said stud- I4 is alsoformed withe. centrally located. through passage or bore.

3 rangement is also shown and described in the aforementioned Patent No. 2,158,824, wherefore a detailed explanation thereof is omitted. Said adjusting nut I5 is also formed with an annular shoulder I5 of such size as to provide an abutment against which said spring I I exerts a force.

The screw member I6 is formed with a head portion I6 and an externally threaded main body portion I6 to effect threaded engagement thereof with the centrally located through passage in stud I4. Said main body portion Hi is also formed with a centrally located recess I6 and a screw driver slot I6 The head portion It of said screw I 6 is formed with an annular shoulder to receive and centrally locate a cylindrical sleeve I! of metal or other suitable material.

The adjusting mechanism is assembled between the compression spring II and the central portion of said U shaped cover I2 as shown in Fig. 1. Said cover I2 is formed with an opening I2 through which extends the cylindrical end portion [4 of stud I4. The adjusting nut I5, while in threaded engagement with the main body portion I4 of stud I4, receives the upper end of said compression spring I I against its aforementioned annular shoulder I5. Due to engagement of projection I 5 with the slot (not shown) in cover I2, the adjusting nut I5 is limited to rectilinear movement with respect to said cover. Thus as stud I4 is rotated as by means of a screwdriver in slot M the adjusting nut I5 effects variation of the degree of compression of spring ll due to the threaded'engagement of stud I4 with nut In order to provide the aforementioned adjusting feature with a definite safe limit beyond which the fiuid line pressure would be undesirably high, the following calibration steps should be adhered to:

The stud I4 is first rotated until the adjusting nut I5 is positioned at a predetermined maximum safe compressive value of spring I I. At this point, with the screw I6 partly threaded into the central opening of said stud I4, a small screwdriver is inserted into slot I6 of member i6. It is then a simple matter to rotate the screw I6 until the cylindrical sleeve I! is brought into abutting relation with the bottom of the adjusting nut I5. When such a point is reached the locking member I8 is thereafter driven down into the through passage in stud I4 until rigid engagement thereof is effected with stud l4 and screw I6 as shown in Fig. 2. Said locking member I8, as shown, is formed with an enlarged end portion having its periphery fluted or knurled and of such shape and dimensions so as to provide a relatively rigid press fit against the wall of the centrally located opening in stud I4. Said member I8 is also formed with an end portion of substantially smaller diameter which is likewise longitudinally fluted or knurled throughout its length so as to effect a rigid press fit or engagement thereof with the centrally located recess I6 of screw I6. It is thus seen that if the locking member I8 is inserted as shown in Fig. 2 when the screw I6 is positioned to prohibit movement of nut I5 beyond the maximum safe limit, it is extremely difficult if not impossible for one to tamper with and change the maximum safe limit of the pressure system. Notwithstanding such limiting feature it is still possible to adjust the compression of spring II within certain predetermined safe limits.

Fig. 3 shows an embodiment wherein screw I I6 is constructed with a small end portion H6 rather than the aforementioned recess I6 (Fig. 2). Such modification requires a locking member II8 constructed with a centrally located longitudinally fluted or knurled recess Ha the surface of which is longitudinally fluted or knurled. With such a construction the locking member I I8 is formed or driven into the passage in stud I4 until rigid engagement thereof is effected with the stud I4 and the smaller end portion II6 of screw I I6, as shown.

The modification in Fig. 3 also shows screw I I6 to be formed with a lower end portion I Hi of reduced transverse dimensions which projects through a centrally located aperture in the bottom wall of the cup-shaped abutting member I I1. Said abutting member I I! and said screw member II6 are rigidly fastened together as by soldering the exposed part of said lower end portion II6 to the bottom wall of member 1. Except for the slight modifications of screw I6, sleeve I! and locking nut I8, both embodiments of my invention herein disclosed utilize parts of like construction and function in substantially the same manner.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

We claim:

1. For an electric switch having a set of cooperating contacts and means including an actuating element operable to effect engagement and disengagement of said contacts, adjustable biasing means associated with the actuating element to bias the same in a given direction comprising, a biasing element, a first member associated with said biasing element and movable to effect variation of said bias, a second member associated with said first member and adjustable to effect movement of said first member, limiting means associated with said second member and operable to afford limited movement of said first member, and locking means associated with said limiting means and said second member to lock the same against relative movement therebe tween.

2. For an electric switch having a set of cooperating contacts and means including an actuating element operable to effect engagement and disengagement of said contacts, adjustable biasing means associated with said actuating element to bias the same in a given direction and comprising a biasing element, a first member associated with said biasing element and movable to effect variation of said bias, a second member formed with an opening and associated with said first member and being adjustable to effect move ment of said first member, limiting means located partially within the opening in said second member and operable to afford limited movement of said first member, and locking means located within said opening in engagement with said second member and said limiting means to lock the same against relative movement therebetween.

3. For an electric switch having a set of coop-- erating contacts and means including an actuating element operable to effect engagement and disengagement of said contacts, in combination, an adjustable biasing element associated with said actuating element to bias the same in a given direction, adjusting means for said biasing element comprising a first member associated with said biasing element and movable to effect variation of said bias, a second member formed with an opening and associated with said first member and being adjustable to efiect movement of said first member, limiting means having an end portion formed with a recess and located partially within said opening in said second member and being operable to afford limited movement of said first member, and locking means located within said opening and said recess to lock said second member and said limiting means against relative movement therebetween.

4. For an electric switch having a set of cooperating contacts and means including an actuating element operable to effect engagement and disengagement of said contacts, in combination, an adjustable biasing element associated with said actuating element to bias the same in a given direction, adjusting means for said biasing element comprising a first member associated with said biasing element and movable to efiect variation of said bias, a second member formed with an opening and associated with said first member and being adustable to effect movement of said first member, limiting means having an end por-- tion formed with a recess and located partially within said opening in said second member and being operable to afford limited movement of said first member, and locking means having a large end portion and a small end portion which are located within said opening and said recess respectively to lock said second member and said limiting means against relative movement therebetween.

5. For an electric switch having a set of cooperating contacts, means including an actuating element operable to efiect engagement and disengagement of said contacts, and an adjustable biasing element associated with said actuating element to bias the same in a given direction, in combination, adjusting means for said biasing element comprising a first member associated with said biasing element and movable to efiect variation of said bias, a second member formed with an opening and associated with said first member and being adjustable to effect movement of said first member, a limiting device having an end portion of cross sectional area smaller than the rest of such device, and being operable to aiiord limited movement of said first member, said end portion being located at least partially within said opening, and locking means comp-rising a plurality of longitudinally fiuted or knurled surfaces in engagement with said opening and 6 said smaller cross sectional end portion of said limiting device to lock said second member and said limiting device against relative movement therebetween.

6. In combination, first and second elongated, externally threaded members each having an enlarged portion at one end thereof respectively, said first member having an axial opening therethrough and the other end of said second member being threadably engaged within said axial opening at the other end of said first member, an internally threaded member threadedly engaging the external threads of said first member and movable relatively to the latter between the enlarged portions of said first and said second members, and a locking device disposed within said axial opening and having force-fitted engagement with each of said first and said second members to prevent relative movement therebetween whereby relative movement between said first member and said internally threaded member is restricted to a selected degree.

7. The combination defined in claim 6, in which said locking device is formed with projecting portions on the surface thereof to effect locking engagement with said first and said second members.

8. The combination defined in claim '7, in which said second member is provided with a recess formed in said other end thereof and said locking device is press-fitted within said recess and said axial opening in said first member.

9. The combination defined in claim '7, in which said second member is provided with a protuberance extending from said other end thereof and said locking device is press-fitted within said axial opening intermediate said first member and said protuberance.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 580,340 Buell Apr. 6, 1897 745,803 Edeline Dec. 1, 1903 913,712 Dyer Mar. 2, 1909 1,093,474 Rolka Apr. 14, 1914 1,890,009 Van Valkenburg Dec. 6, 1932 2,158,824 Kuhn May 16, 1939 2,185,814 Kuhn Jan. 2, 1940 2,224,524 Schmeisser Dec. 10, 1940 2,318,590 Boynton May 11, 1943 2,367,399 Isakson Jan. 16, 1945 

